2-(2&#39;Hydroxyphenyl) benzotriazoles and process for their preparation

ABSTRACT

2-(2&#39;-hydroxyphenyl)benzotriazoles having general formula (I): ##STR1## The above 2-(2&#39;-hydroxyphenyl)benzotriazoles can be used as light stabilizers for organic polymers.

The present invention relates to 2-(2'-hydroxyphenyl)benzotriazoles.

More specifically, the present invention relates to 2-(2'-hydroxyphenyl)benzotriazoles containing a 2,4-imidazolidinedione group or a 2,4-imidazolidinedione-5,5-disubstituted group in the molecule, a process for their preparation and their use as light stabilizers for organic polymers.

The present invention also relates to the polymeric compositions stabilized with the above benzotriazoles and to the end-products obtained from these compositions.

2-(2'-hydroxyphenyl)benzotriazoles which can be used as light stabilizers are known in the art. These benzotriazoles however have various disadvantages. In fact, they are often rather volatile, they have a low thermal stability and, as they sometimes have an absorption at 400 nm, they give the polymers into which they are incorporated, a yellow colouring.

The Applicant has now surprisingly found that 2-(2'-hydroxyphenyl)benzotriazoles containing a 2,4-imidazolidinedione group or a 2,4-imidazolidinedione-5,5-disubstituted group in the molecule, are capable of overcoming the drawbacks of the known art. In fact, the above benzotriazoles have a low volatility (they are therefore able to remain inside the stabilized organic polymer for a longer period) and also a high thermal stability. In addition, they have a low absorption at λ=400 nm and maintain the absorption at the two λ typical of benzotriazoles, at about 300 nm and 340 nm and consequently they do not give a yellow colouring to the polymers into which they are incorporated.

The present invention therefore relates to 2-(2'-hydroxyphenyl)benzotriazoles having general formula ##STR2## wherein: X represents a hydrogen atom; a halogen atom selected from chlorine and bromine; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₁ -C₁₈ alkoxyl group; a cyano group;

R represents a halogen atom selected from chlorine and bromine; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group possibly substituted; a C₇ -C₁₅ arylalkyl or alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group possibly substituted; a linear or branched C₁ -C₁₈ alkoxyl group; a heterocyclic group with 5 or 6 atoms containing at least one heteroatom selected from oxygen, nitrogen and sulfur, said heterocyclic group possibly substituted; a group having the formula: ##STR3## a --COR₄ group or a --NR₅ R₆ group wherein R₄, R₅ and R₆, the same or different, represent a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group possibly substituted; a C₇ -C₁₅ arylalkyl or alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group possibly substituted; a heterocyclic group with 5 or 6 atoms containing at least one heteroatom selected from oxygen, nitrogen and sulfur, said heterocyclic group possibly substituted;

or R represents an ester group having general formula (II), (III) or (IV): ##STR4## or an amide group having general formula (V): ##STR5## wherein R' represents a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group possibly substituted; a C₇ -C₁₅ arylalkyl or alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group possibly substituted; a linear or branched C₁ -C₁₈ alkoxyl group; a heterocyclic group with 5 or 6 atoms containing at least one heteroatom selected from oxygen, nitrogen and sulfur, said heterocyclic group possibly substituted;

or R represents a 4,4'-ethylidenebisphenol group having formula (VI): ##STR6## R₁ represents a hydrogen atom; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched c₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group possibly substituted; a C₇ -C₁₅ arylalkyl or alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group possibly substituted; a heterocyclic group with 5 or 6 atoms containing at least one heteroatom selected from oxygen, nitrogen and sulfur, said heterocyclic group possibly substituted; an acyl group having general formula (VII): ##STR7## or an ester group having general formula (VIII); ##STR8## wherein R' has the same meanings described above; R₂ and R₃, the same or different, represent a hydrogen atom; a linear or branched C₁ -C₁₈ alkyl group; a phenyl group; a heterocyclic group with 5 or 6 atoms containing at least one heteroatom selected from oxygen, nitrogen and sulfur, said heterocyclic group possibly substituted.

The compounds having general formula (I) can be used as light stabilizers for organic polymers.

When the C₅ -C₁₈ cycloalkyl groups, the C₆ -C₁₄ aryl groups and the heterocyclic groups with 5 or 6 atoms are defined as being possibly substituted, these groups are substituted with: halogen atoms selected from chlorine and bromine, linear or branched C₁ -C₁₈ alkyl groups, linear or branched C₂ -C₁₈ alkenyl groups; linear or branched C₂ -C₁₈ alkinyl groups, OH groups, NH groups, SH groups.

Examples of C₁ -C₁₈ alkyl groups are: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, t-amyl, 2-ethylhexyl, n-octyl, 1,1,3,3-tetramethylbutyl, n-do-decyl, 1,1,7,7-tetramethyloctyl, n-octadecyl, etc.

Examples of C₂ -C₁₈ alkenyl groups are: vinyl, propylene, butylene, pentylene, hexylene, etc.

Examples of C₂ -C₁₈ alkinyl groups are: acetylene, propine, butine, 2-butine, etc.

Examples of C₅ -C₁₈ cycloalkyl groups, possibly substituted, are: cyclohexyl, cyclopentyl, methylcyclohexyl, etc.

Examples of C₇ -C₁₅ arylalkyl or alkylaryl groups are: benzyl, 2-phenylethyl, 4-t-butylbenzyl, etc.

Examples of C₆ -C₁₄ aryl groups, possibly substituted, are: phenyl, naphthyl, anthracenyl, 2-hydroxyphenyl, etc.

Examples of C₁ -C₁₈ alkoxyl groups are: methoxyl, ethoxyl, propoxyl, n-butoxyl, etc.

Examples of heterocyclic groups with 5 or 6 atoms, possibly substituted, are: piperidine, morpholine, piperazine, triazole, tetramethylpiperidine, pentamethylpiperidine, tetramethylmorpholine, pentamethylmorpholine, 4-hydroxy-tetramethylpiperidine, etc.

Specific examples of compounds having general formula (I), which in no way limit the scope of the present invention, are: ##STR9##

The compounds having general formula (I) of the present invention can be prepared with various processes.

A further object of the present invention relates to a process for the preparation of 2-(2'-hydroxyphenyl)benzotriazoles having general formula (I).

A process for the preparation of compounds having general formula (I) consists in reacting a 2-(2'hydroxyphenyl)benzotriazole having general formula (IX): ##STR10## wherein X and R have the same meanings defined above, with a 2,4-imidazolidinedione-1,3-dimethylol having general formula (X) or with a 2,4-imidazolidinedione-1-methylol having general formula (Xa), preferably with a 2,4-imidazolidinedione-1-methylol having general formula (Xa): ##STR11## wherein R₂ and R₃ have the same meanings described above, in the presence of concentrated sulfuric acid, for example, at a concentration ranging from 80% to 96%, at a temperature ranging from -5° C. to +80° C. The desired compound is isolated from the mixture thus obtained operating according to processes known in the art such as, for example, by diluting with water, preferably with a water-ice mixture and removing the solid obtained by filtration followed by washing and crystallization in the presence of inert organic solvents.

Inert organic solvents which can be used for the above crystallization are: linear or cyclic aliphatic hydrocarbons such as, for example, hexane, heptane, cyclohexane, methylcyclohexane, etc.; aromatic hydrocarbons such as, for example, toluene, etc.; alcohols such as, for example, methanol, isopropanol, etc.; chlorinated aromatic solvents such as, for example, chlorobenzene, etc.; ketones such as, for example, methylisobutylketone, etc.; monoalkyl ethers of ethylene glycol such as, for example, 2-methoxyethanol (methyl cellosolve), etc.

When in the 2-(2'-hydroxyphenyl)benzotriazoles having general formula (I), R represents an ester group having general formula (II), (III) or (IV), or an amide group having general formula (V), the reaction between the 2-(2'-hydroxyphenyl)benzotriazole having general formula (IX) described above with 2,4-imidazolidinedione-1,3-dimethylol having general formula (X) or with 2,4-imidazolidinedione-1-methylol having general formula (Xa) described above, must be carried out without sulfuric acid. This reaction is carried out in the presence of toluene and p-toluenesulfonic acid as catalyst, at a temperature ranging from room temperature to the boiling point of toluene.

The 2-(2'-hydroxyphenyl)benzotriazoles having general formula (IX) can be prepared as described, for example, in German patent application DE 4.237.817.

The 2,4-imidazolidinedione-1,3-dimethylols having general formula (X) can be prepared as described, for example, in U.S. Pat. No. 4,908,456.

The 2,4-imidazolidinedione-1-methylol having general formula (Xa) can be prepared as described, for example, in Rumenian patent RO 72.413.

The compounds having general formula (I) can also be prepared by reaction of 2-(2'-hydroxyphenyl)benzotriazole having general formula (IX) described above, with a compound having general formula (XI): ##STR12## wherein R₂ and R₃ have the same meanings defined above, in the presence of formaldehyde and sulfuric acid operating as described, for example, in U.S. Pat. No. 4,077,971.

As already mentioned above, the compounds having general formula (I) of the present invention can be used as light stabilizers for a wide range of organic polymers.

Organic polymers capable of being stabilized with the compounds of the present invention are:

(1) polymers of mono-olefins and diolefins such as, for example, polypropylene, polyisobutylene, polybut-1-ene, poly-4-methylpent-1-ene, polyisoprene or polybutadiene; as well as polymers of cyclo-olefins such as, for example, cyclopentene or norbornene; polyethylene (which can be optionally cross-linked) such as, for example, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), branched low density polyethylene (BLDPE)

Polyolefins such as, for example the monolefins mentioned in the above paragraph, preferably polyethylene and polypropylene, can be prepared with various methods known in literature, preferably using the following methods:

(a) radicalic polymerization (generally carried out at a high pressure and high temperature);

(b) catalytic polymerization using a catalyst which normally contains one or more metals of groups IVb, Vb, VIb or VIII of Periodic Table. These metals generally have one or more ligands such as, for example, oxides, halides, alcoholates, ethers, amines, alkyls, alkenyls and/or aryls which can be π- or σ-co-ordinated. These metal complexes can be in free form or supported in substrates such as, for example activated chlorinated magnesium, chlorinated titanium(III), alumina or silicon oxide.

These catalysts can be soluble or insoluble in the reaction medium. Catalysts can be used alone or in the presence of other activators such as, for ex., metal alkyls, metal hydrides, halides of metal alkyls, oxides of metal alkyls or metal alkyloxanes, these metals being elements belonging to groups Ia, IIa and/or IIIa of the Periodic Table. The activators can be modified with other ester, ether, amine or silyl-ether groups. These catalytic systems are usually called Phillips, Standard Oil Indiana, Ziegler(-Natta), TNZ (Du-Pont), metallocene or "single site catalyst" (SSC).

(2) Mixtures of the polymers described under point (1) such as, for example, mixtures of polypropylene with polyisobutylene; mixtures of polypropylene with polyethylene (for example, PP/HDPE, PP/LDPE); mixtures of different types of polyethylene (for example, LDPE/HDPE).

(3) Copolymers of mono-olefins and diolefins with each other or with other vinyl monomers such as, for example, ethylene-propylene copolymers, linear low density polyethylene (LLDPE) and its mixtures with low density polyethylene (LDPE), propylene/but-1-ene copolymers, propylene/isobutylene copolymers, ethylene/but-1-ene copolymers, ethylene/hexene copolymers, ethylene/methylpentene copolymers, ethylene/heptene copolymers, ethylene/octene copolymers, propylene/butadiene copolymers, isobutylene/isoprene copolymers, ethylene/alkyl acrylate copolymers, ethylene/alkyl methacrylate copolymers, ethylene/vinyl acetate copolymers and their copolymers with carbon monoxide or ethylene/acrylic acid copolymers and their salts (ionomers) as well as terpolymers of ethylene with polypropylene and a diene such as, for example, hexadiene, dicyclopentadiene or ethylidene-norbornene; and mixtures of these copolymers with each other or with the polymers cited in paragraph (1) such as, for example, polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinylacetate (EVA) copolymers, LDPE/ethylene-acrylic acid (EAA) copolymers, LLDPE/EVA, LLDPE/EAA, and alternating or "random" polyalkylene/carbon monoxide copolymers and their mixtures with other polymers such as, for example, polyamides.

(4) Hydrocarbon resins (for example, C₅ -C₉) comprising their hydrogenated modifications (for example, adhesive agents) and mixtures with polyalkylene and starch.

(5) Polystyrene, poly(p-methylstyrene), poly(α-methylstyrene).

(6) Copolymers of styrene or α-methylstyrene with dienes or acrylic derivatives such as, for example, styrene/butadiene, styrene/acrylonitrile, styrene/alkyl methacrylate, styrene/butadiene/alkyl acrylate, styrene/butadiene/alkyl methacrylate, styrene/maleic anhydride, styrene/acrylonitrile/methylacrylate; mixtures, having a high impact strength, between copolymers of styrene and another polymer such as, for example, a polyacrylate, a polymer of a diene or an ethylene/propylene/diene terpolymer, block polymers of styrene such as, for example, styrene/butadiene/styrene, styrene/isoprene/styrene, styrene/ethylene/butylene/styrene or styrene/ethylene/propylene/styrene.

(7) Grafted copolymers of styrene or α-methylstyrene such as, for example, styrene in polybutadiene, styrene in polybutadiene or polybutadiene-acrylonitrile copolymers; styrene and acrylonitrile (or methacrylonitrile) in polybutadiene; styrene, acrylonitrile and methylmethacrylate in polybutadiene; styrene and maleic anhydride in polybutadiene; styrene, acrylonitrile and maleic anhydride or maleimide in polybutadiene; styrene and maleimide in polybutadiene; styrene and alkylacrylates or methacrylates in polybutadiene; styrene and acrylonitrile in ethylene/propylene/diene terpolymers, styrene and acrylonitrile in polyalkyl acrylates or polyalkyl methacrylates, styrene and acrylonitrile in acrylate/butadiene copolymers, as well as mixtures of the copolymers listed above with the copolymers cited under point (6) such as, for example, mixtures of known copolymers such as ABS, MBS, ASA or AES;

(8) Polymers containing halogens such as, for example, polychoroprene, chlorinated rubbers, chlorinated or sulfochlorinated polyethyl ene, ethylene and chlorinated ethylene copolymers, homopolymers and copolymers of epichlorohydrin, in particular polymers of vinyl compounds containing halogens such as, for example, polyvinyl chloride, polyvinylidenechloride, polyvinyl fluoride or polyvinylidenefluoride; and also their copolymers such as, for example, vinyl chloride/vinylidenechloride, vinyl chloride/vinyl acetate or vinylidenechloride/vinyl acetate.

(9) Polymers deriving from α,β-unsaturated acids and their derivatives such as, for example, polyacrylates and polymethacrylates, polymethyl methacrylates, polyacrylamides and polyacrylonitriles, modified with butyl acrylate.

(10) Copolymers of monomers according to point (9) with each other or with other unsaturated monomers such as, for example, acrylonitrile/butadiene copolymers, acrylonitrile/alkylacrylate copolymers, acrylonitrile/alkoxyalkyl acrylate copolymers or acrylonitrile/vinyl halide copolymers or acrylonitrile/alkyl methacrylate/butadiene terpolymers.

(11) Polymers deriving from unsaturated alcohols and amines, or their acyl or acetal derivatives such as, for example, polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl butyral, polyallyl phthalate or polyallyl melamine; and also their copolymers with the olefins listed under point (1).

(12) Homopolymers and copolymers of open-chain ethers or cyclic ethers such as, for example, polyalkylene glycols, polyethyleneoxide, polypropylene oxide, or copolymers of the compounds described above with bis-glycidyl ethers.

(13) Polyacetals such as, for example, polyoxymethylene and polyoxymethylenes which contain ethylene oxide as comonomer; polyacetals modified with thermoplastic polyurethanes, acrylates or MBS.

(14) Polyphenylene oxides and sulfides and mixtures of polyphenylene oxides with styrene or polyamide polymers.

(15) Polyurethanes deriving from hydroxyl-terminated polyethers, polyesters or polybutadienes on the one hand and aliphatic or aromatic polyisocyanates on the other, as well as the precursors of the above compounds.

(16) Polyamides and copolyamides deriving from diamines and dicarboxylic acids and/or aminocarboxylic acids or from the corresponding lactams such as, for example, polyamide 4, polyamide 6, polyamide 6/6, 6/10, 6/9, 6/12, 4/6, 12/12, polyamide 11, polyamide 12, aromatic polyamides obtained starting from m-xylene diamine and adipic acid; polyamides prepared from hexamethylenediamine and isophthalic and/or terephthalic acid and with or without an elastomer as modifier, for example, poly-2,4,4-trimethylhexamethylene terephthalamide or poly-m-phenylene isophthalamide; and also block copolymers of the above polyamides with polyolefins, olefinic copolymers, ionomers or elastomers chemically bound or grafted; or with polyethers such as, for example, polyethylene glycol, polypropylene glycol or polytetramethylene glycol; as well as polyamides or copolyamides modified with EPDM or ABS; and polyamides condensed during processing ("RIM polyamide system").

(17) Polyureas, polyimides, polyamide-imides and polybenzoimidazoles.

(18) Polyesters deriving from dicarboxylic acids and diols and/or from hydroxycarboxylic acids or from the corresponding lactones such as, for example, polyethylene terephthalate, polybutylene terephthalate, poly-1,4-dimethylolcyclohexane terephthalate and polyhydroxybenzoates, as well as block copolyether esters deriving from polyethers with hydroxyl-terminated groups; and also polyesters modified with polycarbonates or MBS.

(19) Polycarbonates and polyester carbonates.

(20) Polysulfones, polyethersulfones and polyetherketones.

(21) Cross-linked polymers deriving from aldehydes on the one hand and from phenols, urea and melamines on the other, such as, for example, phenol/formaldehyde resins, urea/formaldehyde resins and melamine/formaldehyde resins.

(22) Drying or non-drying alkyd resins.

(23) Resins based on unsaturated polyesters deriving from copolyesters of dicarboxyl acids saturated and unsaturated with polyhydric alcohols and vinyl compounds as cross-linking agents, and also the above resins containing halogens and having a good flame-resistance.

(24) Cross-linkable acrylic resins deriving from substituted acrylates such as, for example, epoxy acrylates, urethane acrylates or polyester acrylates.

(25) Alkyd resins, resins based on polyesters or acrylated resins cross-linked with melamine resins, urea resins, resins based on polyisocyanates or epoxy resins.

(26) Cross-linked epoxy resins deriving from polyepoxides such as, for example, bis-glycidyl ethers or cycloaliphatic diepoxides.

(27) Natural polymers such as, for example, cellulose, rubber, gelatine, and their derivatives chemically modified to give homologous polymers such as, for example, cellulose acetates, propionates and butyrates, or cellulose ethers such as, for example, methyl-cellulose; as well as hydrocarbon resins ("rosins") or their derivatives.

(28) Mixtures of the above polymers ("polyblends") such as, for example, PP/EPDM, polyamides/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVC/acrylates, POM/thermoplastics PUR, PC/thermoplastics PUR, POM/acrylates, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers, PA/HDPE, PA/PP, PA/PPO.

The compounds having formula (I) of the present invention are particularly useful in the stabilization of polycarbonates.

A further object of the present invention relates to polymeric compositions containing an organic polymer and an effective quantity of one or more compounds having general formula (I).

The compounds having general formula (I) of the present invention can be used as such or combined with other stabilizers, in the above polymeric compositions.

In general, the above compounds having general formula (I) are used in a quantity ranging from about 0.1% to about 5% by weight of the weight of the polymeric compositions to be stabilized, although the quantity used varies according to the substrate to be stabilized and the final application. They are preferably added in a quantity ranging from about 0.5% to about 3% by weight of the weight of the polymeric compositions to be stabilized.

The compounds having general formula (I), possibly in the presence of other additives, can be easily incorporated in the organic polymers to be stabilized using the conventional techniques. This incorporation can take place before or during the formation of the end-product, for example, by mixing the compounds having general formula (I) in powder form with the polymer to be stabilized, or by adding these compounds to the polymer to be stabilized in the molten state or in solution, or applying a solution or suspension of these compounds to the polymer to be stabilized, optionally evaporating the solvent used.

The elastomers can be stabilized as latexes. Another method for incorporating the compounds having general formula (I) in the organic polymers comprises the addition of these before or during the polymerization of the corresponding monomers or before the crosslinking.

The compounds having general formula (I) or their mixtures, can be added to the polymer to be stabilized also in masterbatch form which comprises these compounds in a concentration ranging, for example, from 2.5% to 25% by weight.

The compounds having general formula (I) can be conveniently incorporated in the organic polymers to be stabilized by means of the following methods:

in the form of emulsion or suspension (for example, in the case of latexes or polymers in emulsion);

as a mixture of powders in the case of the conventional addition of additional compounds or mixtures of organic polymers;

directly adding to the apparatus used for processing the organic polymers (for example, extruders, internal mixers, etc.);

in the form of solution or molten product.

The polymeric compositions stabilized as described above can be converted to end-products such as, for example, fibers, films, tapes, sheets, multi-layer sheets, containers, tubes and other forms, by means of methods known in the art such as, for example, casting, hot moulding, spinning, extrusion or injection molding.

The present invention therefore also relates to the use of the above polymeric compositions for the production of end-products.

The use of multi-layer systems is also of interest, in which one of the above compositions having a relatively high content of a compound having general formula (I), for example, between 5% and 15% by weight, is applied in the form of a thin film (10-100 μm in thickness) to a shaped article consisting of a polymer not containing or containing a small quantity of a compound having general formula (I). This application can be carried out during the formation of said article, for example, by means of a co-extrusion. The application can also be effected however on the end shaped-article, for example, by lamination with a film or by coating with a solution. The surface layer or layers of the end-article act as a UV filter which protects the inside of the articles from the deteriorating action of UV light. The upper layer preferably contains from 5% to 15% by weight, more preferably from 5% to 10% by weight, of at least one compound having general formula (I).

The use of the above compositions for the production of multi-layer systems, in which the upper layer having a thickness of 10-100 μm comprises these compositions, whereas the internal layer does not contain or contains a small quantity of a compound having general formula (I) consequently represents a further object of the present invention.

The polymers stabilized as described above have a high resistance to degradation caused by atmospheric agents, in particular a high resistance to UV light. They are therefore capable of maintaining their colour and gloss for a long period even when exposed to external agents.

The compositions described above can also be used as compositions for coating or painting ("coating compositions") such as, for example, paints, lacquers, plastic-based compositions.

For the purposes of the present invention, coating or painting compositions are preferred in which the organic polymer is selected from:

(a) a thermoplastic polymer selected from thermoplastic polymers containing heteroatoms, in particular nitrogen, sulfur and/or oxygen, in the main chain, styrene copolymers, grafted styrene polymers and polymethyl methacrylates (PMMA); or

(b) a paint ligand.

Specific examples of thermoplastic polymers (a) containing heteroatoms, in particular nitrogen, sulfur and/or oxygen, in the main chain, are listed above under points 13 to 20. Among these, polycarbonates, polyesters, polyamides, polyacetals, polyphenylene oxides and polyphenylene sulfides are preferred; particularly preferred are polycarbonates, polyesters such as, for example, polyethylene terephthalate (PET), and polyamides (PA) such as, for example, PA 6 and PA 6/6; even more preferred are polycarbonates.

Specific examples of styrene copolymers and grafted styrene polymers (a) are listed above under points 6 and 7.

Paint ligands (b) can comprise at least one of the organic polymers specified above. Specific examples of paints containing specific ligands are:

1. paints based on alkyd resins, acrylic resins, polyester resins, epoxy resins or melamine resins, which can be cross-linked at a low or high temperature, or mixtures of these resins, to which a cross-linking agent is optionally added;

2. polyurethane paints with two components based on acrylic resins containing hydroxyl groups, polyester resins or polyether resins and aliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;

3. polyurethane paints with one component based on block isocyanates, isocyanurates or polyisocyanates which are unblocked during oven treatment;

4. paints with two components based on (poly)ketoimines and aliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;

5. paints with two components based on (poly)ketoimines and an unsaturated acrylic resin or a polyacetoacetate resin or a methyl methalcrylamidoglycolate;

6. paints with two components based on polyacrylates containing a carboxylic group or an amine group and polyepoxides;

7. paints with two components based on acrylic resins containing an anhydride group and a polyhydroxyl or polyamine compound;

8. paints with two components based on (poly)-oxazoline line and acrylic resins containing an anhydride group or unsaturated acrylic resins or aliphatic or aromatic isocyanates, or isocyanurates or polyisocyanates;

9. paints with two components based on unsaturated polyacrylates and polymalonates;

10. thermoplastic polyacrylic paints based on thermo-plastic acrylic resins or non-self-crosslinking acrylic resins combined with etherified melamine resins;

11. systems for paints based on siloxane-modified acrylic resins;

12. systems for paints based on fluoro-modified acrylic resins; and

13. systems for paints based on allyl glycidyl ethers.

The paints can be applied as one or two layers ("one- or two-coat") of coating and the stabilizing compounds having formula (I) are preferably added to the upper colourless coating.

The paints can be applied to the substrate (metal, plastic, wood, etc.) using the conventional methods such as, for example, brushing, spraying, pouring, dipping or electrophoresis.

A preferred embodiment of the present invention consists in paints or coatings (for example car coating) comprising at least one compound having general formula (I). Ligands which can be used for the purpose are, for example, those listed above.

The compounds having general formula (I) of the present invention can be combined, as already mentioned above, with other conventional additives or their mixtures. These additives are added in a quantity ranging from about 0.1% to about 5% by weight of the weight of the polymeric compositions to be stabilized, preferably from about 0.5% to about 3% by weight. Some of the additives used are listed below as an example.

1. Antioxidants

1.1 Alkylated monophenols such as, for example:

2,6-di-t-butyl-4-methylphenol;

2-t-butyl-4,6-dimethylphenol;

2,6-di-t-butyl-4-ethylphenol;

2,6-di-t-butyl-4-n-butylphenol;

2,6-di-t-butyl-4-isobutylphenol;

2,6-di-cyclopentyl-4-methylphenol;

2-(α-methylcyclohexyl)-4,6-dimethylphenol;

2,6-dioctadecyl-4-methylphenol;

2,4,6-tricyclohexylphenol;

2,6-di-t-butyl-4-methoxymethylphenol;

2,6-di-nonyl-4-methylphenol;

2,4-dimethyl-6-(1'-methylundec-1'-yl)phenol;

2,4-dimethyl-6-(1'emthylhectadec-1'-yl)phenol;

2,4-dimethyl-6-(1'-methyltridec-1'-yl)phenol; and their mixtures.

1.2 Alkylthiomethylphenols such as, for example:

2,4-dioctylthiomethyl-6-t-butylphenol;

2,4-dioctylthiomethyl-6-methylphenol;

2,4-dioctylthiomethyl-6-ethylphenol;

2,6-didodecylthiomethyl-4-nonylphenol.

1.3 Hydroquinones and alkylated hydroquinones such as, for example:

2,6-di-t-butyl-4-methoxyphenol;

2,5-di-t-butylhydroquinone;

2,5-di-t-amylhydroquinone;

2,6-diphenyl-4-octadecyloxyphenol;

2,6-di-t-butylhydroquinone;

2,5-di-t-butyl-4-hydroxyanisol;

3,5-di-t-butyl-4-hydroxyanisol;

3,5-di-t-butyl-4-hydroxyphenyl stearate;

bis(3,5-di-t-butyl-4-hydroxyphenyl)adipate.

1.4 Tocopherols such as, for example: α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and their mixtures (Vitamin E).

1.5 Hydroxylated thiophenyl ethers such as, for example:

2,2'-thiobis-(6-t-butyl-4-methylphenol);

2,2'-thiobis-(4-octylphenol);

4,4'-thiobis-(6-t-butyl-3-methylphenol);

4,4'-thiobis-(6-t-butyl-2-methylphenol);

4,4'-thiobis-(3,6-di-sec-amylphenol);

4,4'-bis-(2,6-dimethyl-4-hydroxyphenyl)disulfide.

1.6 Alkylidene-bisphenols such as, for example:

2,2'-methylenebis-(6-t-butyl-4-methylphenol);

2,2'-methylenebis-(6-t-butyl-4-ethylphenol);

2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)phenol];

2,2'-methylenebis(4-methyl-6-cyclohexylphenol);

2,2'-methylenebis(6-nonyl-4-methylphenol);

2,2'-methylenebis(4,6-di-t-butylphenol);

2,2'-ethylidenebis(4,6-di-t-butylphenol);

2,2'-ethylidenebis(6-t-butyl-4-isobutylphenol);

2,2'-methylenebis[6-(α-methylbenzyl)-4-nonylphenol];

2,2'-methylenebis[6-(α,α-dimethylbenzyl)-4-nonylphenol];

4,4'-methylenebis(2,6-di-t-butylphenol);

4,4'-methylenebis(6-t-butyl-2-methylphenol);

1,1-bis-(5-t-butyl-4-hydroxy-2-methylphenyl)butane;

2,6-bis-(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol;

1,1,3-tris-(5-t-butyl-4-hydroxy-2-methylphenyl)butane;

1,1-bis-(5-t-butyl-4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane;

ethyleneglycol bis[3,3-bis(3'-t-butyl-4'-hydroxyphenyl)butyrate];

bis(3-t-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene;

bis[2-(3'-t-butyl-2'-hydroxy-5'-methylbenzyl)-6-t-butyl-4-methylphenyl]terephthalate;

1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane;

2,2-bis(3,5-di-t-butyl-4-hydroxyphenyl)propane;

2,2-bis(5-t-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane;

1,1,5,5-tetra(5-t-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7 Benzyl compounds containing O, N or S such as, for example:

3,5,3',5'-tetra-t-butyl-4,4'-dihydroxydibenzyl ether;

octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate;

tris(3,5-di-t-butyl-4-hydroxybenzyl)amine;

bis(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate; bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide;

iso-octyl-3,5-di-t-butyl-4-hydroxybenzylmercaptoacetate;

1.8 Hydroxybenzylated malonates such as, for example:

dioctadecyl-2,2-bis(3,5-di-t-butyl-2-hydroxybenzyl)malonate;

dioctadecyl-2-(3-t-butyl-4-hydroxy-5-methylbenzyl)malonate;

didodecylmercaptoethyl-2,2-bis (3,5-di-t-butyl-4-hydroxybenzyl)malonate;

bis[4-(1,1,3,3-tetramethylbutyl)phenyl]-2,2-bis(3,5-di-t-butyl-4-hydroxybenzyl)malonate.

1.9 Aromatic hydroxybenzyl compounds such as, for example:

1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene;

1,4-bis-(3,5-di-t-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene;

2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)phenol.

1.10 Triazine compounds such as, for example:

2,4-bis(octylmercapto)-6-(3,5-di-t-butyl-4-hydroxyaniline)-1,3,5-triazine;

2-octylmercapto-4,6-bis(3,5-di-t-butyl-4-hydroxyaniline)-1,3,5-triazine;

2-octylmercapto-4,6-bis(3,5-di-t-butyl-4-hydroxyphenoxy)-1,3,5-triazine;

2,4,6-tris-(3,5-di-t-butyl-4-hydroxyphenoxy)-1,2,3-triazine;

1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)isocyanurate;

1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate;

2,4,6-tris-(3,5-di-t-butyl-4-hydroxyphenylethyl)-1,3,5-triazine;

1,3,5-tris(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine;

1,3,5-tris-(3,5-dicyclohexyl-4-hydroxybenzyl) isocyanurate.

1.11 Benzylphosphonates such as, for example:

dimethyl-2,5-di-t-butyl-4-hydroxybenzylphosphonate;

diethyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate;

dioctadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate;

dioctadecyl-5-t-butyl-4-hydroxy-3-methylbenzylphosphonate;

calcium salts of monoethyl ester of 3,5-di-t-butyl-4-hydroxybenzylphosphonic acid.

1.12 Acylaminophenols such as, for example:

4-hydroxylauranilide;

4-hydroxystearanilide;

octyl-N-(3,5-di-t-butyl-4-hydroxyphenyl)carbamate.

1.13 Esters of β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid with monohydric or polyhydric alcohols such as, for example:

methanol, ethanol, octanol, octadecanol, 1,6-hexandiol, 1,9-nonandiol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thioundecanol, 3-thiopentadecanol, trimethylhexandiol, trimethylolpropane, 4-hydroxymethyl-1-phospho-2,6,7-trioxabicyclo[2.2.2]octane.

1.14 Esters of β-(5-t-butyl-4-hydroxy-3-methylphenyl)propionic acid with monohydric or polyhydric alcohols such as, for example:

methanol, ethanol, octanol, octadecanol, 1,6-hexandiol, 1,9-nonandiol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thioundecanol, 3-thiopentadecanol, trimethylhexandiol, trimethylolpropane, 4-hydroxymethyl-1-phospho-2,6,7-trioxabicyclo[2.2.2]octane.

1.15 Estersof β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with monohydric or polyhydric alcohols such as, for example:

methanol, ethanol, octanol, octadecanol, 1,6-hexandiol, 1,9-nonandiol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thioundecanol, 3-thiopentadecanol, trimethylhexandiol, trimethylolpropane, 4-hydroxymethyl-1-phospho-2,6,7-trioxabicyclo[2.2.2]octane.

1.16 Esters of (3,5-di-t-butyl-4-hydroxyphenyl)acetic acid with monohydric or polyhydric alcohols such as, for example:

methanol, ethanol, octanol, octadecanol, 1,6-hexandiol, 1,9-nonandiol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thioundecanol, 3-thiopentadecanol, trimethylhexandiol, trimethylolpropane, 4-hydroxymethyl-1-phospho-2,6,7-trioxabicyclo[2.2.2]octane.

1.17 Amides of β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid such as, for example:

N,N'-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine;

N,N'-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)trimethylenediamine;

N,N'-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hydrazine.

2. Ultra-violet Ray and Light Stabilizers.

2.1 Derivatives of 2-(2'-hydroxyphenyl)benzotriazoles such as, for example:

2-(2'-hydroxy-5'methylphenyl)benzotriazole;

2-(3',5'-di-t-butyl-2'-hydroxyphenyl)benzotriazole;

2-(5'-t-butyl-2'-hydroxyphenyl)benzotriazole;

2-[2'-hydroxy-5'-(1,1,3,3-tetramethylbutyl)phenyl]benzotriazole;

2-(3',5'-di-t-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole;

2-(3'-t-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole;

2-(3'-sec-butyl-5'-t-butyl-2'-hydroxyphenyl)benzotriazole;

2-(2'-hydroxy-4'-octyloxyphenyl)-benzotriazole;

2-(3',5'-di-t-amyl-2'-hydroxyphenyl)-benzotriazole;

2-[3',5'-bis(α,α-dimethylbenzyl)-2'-hydroxyphenyl]benzotriazole;

mixtures of 2-[3'-t-butyl-2'-hydroxy-5'-(2-octylo-xycarbonylethyl)phenyl)-5-chorobenzotriazole, 2-[3'-t-butyl-5'-(2-(2-ethylhexyloxy)carbonylethyl)-2'-hydroxyphenyl]-5-chlorobenzotriazole, 2-[3'-t-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl) phenyl]-5-chlorobenzotriazole, 2-[3'-t-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl)phenyl]benzotriazole, 2-[3'-t-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl]benzotriazole, 2-[3'-t-butyl-5'-(2-(2-ethylhexyloxy)carbonylethyl)-2'-hydroxyphenyl)benzotriazole, 2-(3'dodecyl-2'-hydroxy-5'-methylphenyl)benzotriazole and 2-[3'-t-butyl-2'-hydroxy-5'-(2-iso-octyloxycarbonylethyl)phenyl]benzotriazole, 2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-yl-phenol]; esterification product of 2-[3'-t-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl]-2H-benzotriazole with polyethylene glycol 300; [R--CH₂ CH₂ --COO(CH₂)₃ ]₂ wherein R=3'-t-butyl-4-hydroxy-5'-2H-benzotriazol-2-yl-phenyl.

2.2 Derivatives of 2-hydroxybenzophenones such as, for example: 4-hydroxy-; 4-methoxy-; 4-octyloxy-; 4-decyloxy-; 4-dodecyloxy-; 4-benzyloxy-; 4,2',4'-trihydroxy-; 2'-hydroxy-4,4'-dimethoxy.

1.3 Esters of benzoic acids, optionally substituted, such as, for example: phenyl salicylate, 4-t-butylphenyl salicylate, octylphenyl salicylate, benzoyl-resorcinol, bis(4-t-butylbenzoyl)-resorcinol, dibenzoyl-resorcinol, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate, octadecyl-3,5-di-t-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate.

2.4 Acrylates such as, for example, ethyl or isoctyl α-cyano-β,β-diphenylacrylate; methyl α-carbomethoxycinnamate, methyl or butyl α-cyano-β-methyl-p-methoxycinnamate, methyl α-carbomethoxy-p-methoxy-cinnamate, N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5 Nickel compounds such as, for example, complexes of 2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)phenol], for example 1:1 or 1:2 complexes, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of monoalkyl esters of 4-hydroxy-3,5-di-t-butyl-benzyl-phosphonic acid, such as methyl or ethyl esters, nickel complexes with ketoximes such as 2-hydroxy-4-methylphenyl undecyl ketoxime, nickel complexes of l-phenyl-4-lauroyl-5-hydroxypyrazol with or without additional ligands.

2.6 Sterically hindered amines such as, for example:

bis(2,2,6,6-tetramethyl-piperidyl)sebacate;

bis(2,2,6,6-tetramethyl-piperidyl)succinate; poly-methylpropyl-3-oxy[4-(2,2,6,6-tetramethyl)pi-peridinyl]siloxane;

bis(1,2,2,6,6-pentamethyl-piperidyl)sebacate;

bis(1,2,2,6,6-pentamethyl-piperidyl)n-butyl-3,5-di-t-butyl-4-hydroxybenzylmalonate;

condensation product between 1-(2-hydroxyethyl)-2,2,6,6-tetra-4-hydroxypiperidine and succinic acid;

condensation product between N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-t-octylamino-2,6-dichloro-1,3,5-triazine;

tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate;

tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butane-tetracarboxylate;

1,1'-(1,2-ethanodyl)bis(3,3,5,5-tetramethylpiperazinone;

4-benzoyl-2,2,6,6-tetramethylpiperidine;

4-stearyloxy-2,2,6,6-tetramethylpiperidine;

bis (1,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5-di-t-butylbenzyl)malonate;

3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4-dione;

bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate;

bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate;

condensation product between N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-morpholine-2,6-dichloro-1,3,5-triazine;

condensation product between 2-chloro-4,6-di-(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane;

condensation product between 2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane;

8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3-8-triazaspiro[4.5]decano-2,4-dione;

3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidin-2,5-dione;

3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidin-2,5-dione.

2.7 Oxamides such as, for example:

4,4'-dioctyloxyoxanilide;

2,2'-diethoxyoxanilide;

2,2'-dioctyloxy-5,5'-di-t-butoxanilide;

2,2'-didodecyloxy-5,5'-di-t-butoxanilide;

2-ethoxy-2'-ethyloxanilide;

N,N'-bis(3-dimethylaminopropyl)oxamide;

2-ethoxy-5-t-butyl-2'-ethoxanilide and its mixtures with 2-ethoxy-2'-ethyl-5,4'-di-t-butoxanilide; and mixtures of disubstituted ortho- and paramethoxy anilides and mixtures of disubstituted ortho and para-ethoxy anilides.

2.8 2-(2-hydroxyphenyl)-1,3,5-triazines such as, for example:

2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine;

2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis (2,4-dimethylphenyl)-1,3,5-triazine;

2-(2,4-dihydroxyphenyl)-4,6-bis (2,4-dimethylphenyl)-1,3,5-triazine;

2,4-bis-(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine;

2-(2-hydroxy)-4,6-bis (4-methylphenyl)-1,3,5-triazine;

2-(2-hydroxy-4-dodecyloxyphenyl)-4-bis(2,4-dimethylphenyl)-1,3,5-triazine;

2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine;

2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-triazine.

3. "Metal-deactivators" such as, for example: N,N-diphenyloxamide, N-salicylal-N'-salicyloyl-hydrazine, N,N'-bis(salicyloyl)hydrazine; N,N'-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hydrazine, 3-salicyloylamino-1,2,4-triazole, bis(benzylidene)o-xalyl dihydrazide, oxanilide, isophthaloyl dihydrazide, sebacoyl bisphenylhydrazide, N,N'-diacetyladipoyl dihydrazide, N,N'-bis(salicyloyl)oxallyldihydrazide, N,N'-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites and phosphonites such as, for example: triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-t-butylphenyl)phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, bis(2,5-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, diisodecyloxypentaerythritol diphosphite, bis (2,4-di-t-butyl-6-methylphenyl)pentaerythritol diphosphite, bis[2,4,5-tris(t-butylphenyl)]pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis-(2,4-di-t-butyl-phenyl)-4,4'-diphenylilenediphosphonite, 5-iso-octyloxy-2,4,8,10-tetra-t-butyl-12H-di-benzo[d,g]-1,3,2-dioxaphosphocine, 6-fluoro-2,4,8,10-tetra-t-butyl-12-methyl-dibenzo[d,g]-1,3,2-dioxaphosphocine, bis(2,4-di-t-butyl-6-methylphenyl)methylphosphite, bis(2,4-di-t-butyl-6-methylphenyl)ethylphosphite.

5. Agents which are capable of destroying peroxides such as, for example, esters of β-thiodipropionic acid such as lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or zinc salt of 2-mercaptobenzimidazole, zinc dibutyldithiocarbamate, dioctadecyldisulfide pentaerythritol tetrakis (β-dodecylmercapto)propionate.

6. Stabilizers of polyamides such as, for example, copper salts combined with compounds of iodine and/or phosphorous, divalent manganese salts.

7. Basic co-stabilizers such as, for example: melamine, polyvinylpyrrolidone, dicyanodiamide, triallyl cyanurate, derivatives of urea, derivatives of hydrazine, amines, polyamides, polyurethanes, salts of alkaline metals and salts of earth-alkaline metals of fatty acids such as, for example, Ca-stearate, Zn-stearate, Mg-stearate, Mg-behenate, Na-ricinoleate, K-palmitate, antimonium-pyrocatecholate, tin-pyrocatecholate.

8. Nucleating agents such as, for example: 4-t-butylbenzoic acid, adipic acid, diphenylacetic acid.

9. Fillers and reinforcing agents such as, for example: calcium carbonate, silicates, glass fibres, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite.

10. Other additives such as, for example: plasticizers, lubricants, emulsifying agents, pigments, optical brighteners, flame-retardants (for example, bromides, chlorides, phosphides and phosphorous/halogen mixtures), antistatic agents, blowing agents, thiosynergizing agents such as, for example, dilauryl thiodipropionate or distearyl thiodipropionate.

11. Benzofuranones and indolinones such as, for ex.:

3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-t-butylbenzofuran-2-one;

5,7-di-t-butyl-3-[4-(2-stearoyloxyethoxy)phenyl]benzofuran-2-one;

3,3'-bis[5,7-di-t-butyl-3-[4-(2-hydroxyethoxy)phenyl]benzofuran-2-one];

5,7-di-t-butyl-3-(4-ethoxyphenyl)benzofuran-2-one;

3-(4-acetoxy-3,5-dimethylphenyl)-5,7-di-t-butyl-benzofuran-2-one;

3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-t-butyl-benzofuran-2-one;

or those described in U.S. Pat. Nos. 4,325,863, 4,338,244, 5,175,312, 5,216,052, 5,252,643, 4,316,611, 4,316,622, 4,316,876 or in European patent applications 589,839 and 591,102.

Some illustrative but non-limiting examples are provided hereunder for a better understanding of the present invention and for its embodiment.

EXAMPLE 1 Preparation of Compound Nr. 1 Having the Formula ##STR13## Procedure (a)

11.3 g (0.05 moles) of 2-(2'-hydroxy-5'-methyl)benzotriazole in 50 ml of concentrated sulfuric acid at 96% are charged into a 4-necked 250 ml flask, equipped with a mechanical stirrer, drip funnel, thermometer and condenser, the temperature being maintained at between -5° C. and 0° C. 9.0 g (0.057 moles) of an aqueous solution at 33% of 1-methylol-5,5-dimethylhydantoin are then slowly added dropwise in 30 minutes, maintaining the temperature at between -5° C. and 0° C.

The above mixture is left to rise to 20° C. under stirring, is then maintained at this temperature, continually under stirring, for 5 hours and is subsequently heated to 70° C. for a further 2 hours. The raw product obtained is poured into 400 ml of water-ice, filtered, then washed until neutral pH.

A solid is thus obtained which is crystallized with 200 ml of 2-methoxyethanol. 15 g (yield 82%) of a white powder corresponding to Compound Nr. 1 whose characteristics are provided below, are obtained from this crystallization.

Procedure (b)

11.3 g (0.05 moles) of 2-(2'-hydroxy-5'-methyl)benzotriazole in 67 ml of concentrated sulfuric acid at 96% are charged into a 4-necked 250 ml flask, equipped with a mechanical stirrer, drip funnel, thermometer and condenser, the temperature being maintained at between -5° C. and 0° C. 9.4 g (0.05 moles) of an aqueous solution at 60% of 1,3-dimethylol-5,5-dimethylhydantoin are then slowly added dropwise in 30 minutes, maintaining the temperature at between -5° C. and 0° C.

The above mixture is left to rise to 20° C. under stirring, is then maintained at this temperature, continually under stirring, for 4 hours and is subsequently heated to 80° C. for a further 2 hours. The raw product obtained is poured into 400 ml of water-ice, filtered, then washed until neutral pH.

A solid is thus obtained which is crystallized with 200 ml of 2-methanol. 13 g (yield 71%) of a white powder corresponding to Compound Nr. 1 are obtained from this crystallization, with the following characteristics:

melting point (DSC): 236° C. I.R. in nujols (cm⁻¹): 3100, 1770, 1714. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 1.38 (s, 6H); 2.38 (s, 3H); 4.7 (s, 2H); 7.3 (d, J=1.6 Hz, 1H); 7.5 (dd, 2H); 7.9 (dd, 2H); 8.15 (d, J=1.6 Hz, 1H); 8.3 (brs, 1H); 11.6 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 20.3; 22.8; 36.3; 63.7; 117.6; 120.8; 124.8; 127; 127.8; 129.6; 131.7; 142.8; 145; 155.4; 177.3. Mass spectrometry (m/e): [M.sup.•+ ion]: 365 (100)*; 279 (91)*; 253 (53)*; 238 (30)*; 91 (9)*; 77 (13)*.

*: the relative intensity is indicated in brackets.

Elemental Analysis:

    ______________________________________                                         ELEMENTAL   C.sub.19 H.sub.19 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  62.47%       5.21%   19.17%                                          FOUND 62.44% 5.19% 19.15%                                                    ______________________________________                                    

EXAMPLE 2 Preparation of Compound Nr. 2 Having the Formula ##STR14##

16.15 g (0.05 moles) of 2-(2'-hydroxy-5'-t-octyl)benzotriazole in 67 ml of concentrated sulfuric acid at 98% are charged into a 4-necked 250 ml flask, equipped with a mechanical stirrer, drip funnel, thermometer and condenser, the temperature being maintained at between -5° C. and 0° C. 9.4 g (0.05 moles) of an aqueous solution at 60% of 1,3-dimethylol-5,5-dimethylhydantoin are then slowly added dropwise in 30 minutes, maintaining the temperature at between -5° C. and 0° C.

The above mixture is left to rise to 20° C. under stirring, is then maintained at this temperature, continually under stirring, for 3 hours and is subsequently heated to 80° C. for a further 3 hours. The raw product obtained is poured into 400 ml of water-ice, filtered, then washed until neutral pH.

A solid is thus obtained which is crystallized with 200 ml of hexane. 19 g (yield 82%) of a white powder corresponding to Compound Nr. 2 are obtained from this crystallization, with the following characteristics:

melting point (DSC): 138° C. I.R. in nujols (cm⁻¹): 3100, 1770, 1714. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 0.8 (s, 9H); 1.37 (s, 6H); 1.4 (s, 6H); 1.7 (s, 2H); 4.7 (s, 2H); 7.4 (dd, 2H); 7.5 (d, J=2 Hz, 1H); 7.9 (dd, 2H); 8.3 (d, J=2 Hz, 1H); 8.6 (brs, 1H); 11.6 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 22.7; 28.9; 31; 32; 36.6; 38.2; 56.6; 63.6; 117.6; 118.3; 124; 126; 127; 129; 142.2; 142.7; 144;8 155; 177. Mass spectrometry (m/e): [M.sup.•+ ion]: 392 (100)*; 264 (74)*; 463 (53)*; 41 (10)*.

*: the relative intensity is indicated in brackets.

Elemental Analysis:

    ______________________________________                                         ELEMENTAL   C.sub.26 H.sub.33 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  67.39%       7.13%   15.00%                                          FOUND 67.21% 7.04% 14.80%                                                    ______________________________________                                    

EXAMPLE 3 Preparation of Compound Nr. 3 Having the Formula ##STR15##

The following products are charged into a 3-necked 100 ml flask, equipped with reflux, thermometer and drip funnel: 5.0 g (0.014 moles) of Compound Nr. 1 obtained as described in Example 1, 40 ml of dimethylformamide, 1.93 g (0.014 moles) of potassium carbonate and finally, dropwise, 2 g (0.0147 moles) of methyl iodide; the reaction is maintained, under stirring, at room temperature and is controlled by T.L.C. ("Thin Layer Chromatography") using hexane/ethyl acetate as eluants in a ratio of 1/1.

At the end of the reaction, the solvent is eliminated by distillation, methylene chloride is added to the raw product which is then washed with water. The organic phase is separated, anhydrified on sodium sulfate, filtered and, finally, evaporated.

The product obtained is crystallized from heptane obtaining 3.7 g (yield 70%) of a white solid corresponding to Compound Nr. 3 having the following characteristics:

melting point: 208° C.-210° C. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 1.35 (s, 6H); 2.36 (s, 3H); 3.00 (s, 3H); 4.72 (s, 2H); 7.28 (d, J=1.6 Hz, 1H); 7.48 (dd, 2H); 7.90 (dd, 2H); 8.13 (d, J=1.6 Hz, 1H); 11.60 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 20.50; 22.80; 24.90; 36.50; 62.20; 117.50; 120.80; 124.60; 127.20; 127.80; 129.50; 131.70; 142.80; 145.00; 156.00; 177.00.

Elemental analysis:

    ______________________________________                                         ELEMENTAL   C.sub.20 H.sub.21 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  63.3%        5.50%   18.5%                                           FOUND 63.0% 5.45% 18.1%                                                      ______________________________________                                    

EXAMPLE 4 Preparation of Compound Nr. 4 Having the Formula ##STR16##

The following products are charged into a 3-necked 100 ml flask, equipped with reflux, thermometer and drip funnel: 5.0 g (0.014 moles) of Compound Nr. 1 obtained as described in Example 1, 40 ml of dimethylformamide, 1.93 g (0.014 moles) of potassium carbonate and finally, dropwise, 1.8 g (0.0147 moles) of propylbromide; the reaction mixture is heated to 150° C. for 2 hours and is controlled by T.L.C. ("Thin Layer Chromatography") using hexane/ethyl acetate as eluants in a ratio of 2/1.

At the end of the reaction, the solvent is eliminated by distillation, methylene chloride is added to the raw product which is then washed with water, then with acid water and finally again with water. The organic phase is separated, anhydrified on sodium sulfate, filtered and, finally, evaporated.

The product obtained is crystallized from heptane obtaining 4.3 g (yield 75%) of a white solid corresponding to Compound Nr. 4 having the following characteristics:

melting point: 120° C.-123° C. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 0.90 (t, 3H); 1.30 (s, 6H); 1.65 (m, 2H); 2.30 (s, 3H); 3.50 (t, 3H); 4.68 (s, 2H); 7.22 (d, J=1.6 Hz, 1H); 7.40 (dd, 2H); 7.80 (dd, 2H); 8.00 (d, J=1.6 Hz, 1H); 11.50 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 11.00; 20.60; 21.40; 22.90; 36.50; 40.40; 61.90; 117.60; 120.00; 124.80; 127.40; 127.80; 129.50; 131.70; 142.80; 145.00; 156.10; 176.90.

Elemental analysis:

    ______________________________________                                         ELEMENTAL   C.sub.22 H.sub.25 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  64.9%        6.10%   17.20%                                          FOUND 64.3% 5.85% 17.03%                                                     ______________________________________                                    

EXAMPLE 5 Preparation of Compound Nr. 5 Having the Formula ##STR17##

The following products are charged into a 3-necked 100 ml flask, equipped with reflux, thermometer and drip funnel: 5.0 g (0.014 moles) of Compound Nr. 1 obtained as described in Example 1, 40 ml of dimethylformamide, 1.93 g (0.014 moles) of potassium carbonate and finally, dropwise, 2.8 g (0.0147 moles) of bromooctane; the reaction mixture is heated to 120° C. and is controlled by T.L.C. ("Thin Layer Chromatography") using hexane/ethyl acetate as eluants in a ratio of 2/1.

At the end of the reaction, the solvent is eliminated by distillation and methylene chloride is added to the raw product which is then washed with water, then with acid water and finally again with water. The organic phase is separated, anhydrified on sodium sulfate, filtered and, finally, evaporated.

The product obtained is crystallized from heptane obtaining 4.7 g (yield 71%) of a white solid corresponding to Compound Nr. 5 having the following characteristics:

melting point: 95° C.-98° C. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 0.80 (t, 3H); 1.20 h(m, 10H); 1.30 (s, 6H); 1.50 (t, 2H); 2.40 (s, 3H); 3.50 (t, 2H); 4.70 (s, 2H); 7.20 (d, J=1.6 Hz, 2H); 7.50 (dd, 2H); 7.90 (dd, 2H); 8.10 (d, J=1.6 Hz, 1H); 11.60 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 14.00; 20.60; 22.60; 22.90; 28.00; 28.70; 29.10; 31.80; 36.50; 38.90; 62.00; 117.60; 120.80; 124.80; 127.50; 127.80; 129.50; 131.70; 142.80; 145.10; 156.10; 176.90.

Elemental analysis:

    ______________________________________                                         ELEMENTAL   C.sub.27 H.sub.35 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  67.9%        7.34%   14.70%                                          FOUND 67.1% 7.29% 14.20%                                                     ______________________________________                                    

EXAMPLE 6 Preparation of Compound Nr. 6 Having the Formula ##STR18##

The following products are charged into a 3-necked 100 ml flask, equipped with reflux, thermometer and drip funnel: 5.0 g (0.014 moles) of Compound Nr. 1 obtained as described in Example 1, 40 ml of dimethylformamide, 1.93 g (0.014 moles) of potassium carbonate and finally, dropwise, 2.5 g (0.0147 moles) of benzylbromide; the reaction mixture is heated to 130° C. and is controlled by T.L.C. ("Thin Layer Chromatography") using hexane/ethyl acetate as eluants in a ratio of 1/1.

At the end of the reaction, the solvent is eliminated by distillation and methylene chloride is added to the raw product which is then washed with water, then with acid water and finally again with water. The organic phase is separated, anhydrified on sodium sulfate, filtered and, finally, evaporated.

The product obtained is crystallized from heptane obtaining 4.1 g (yield 65%) of a white solid corresponding to Compound Nr. 6 having the following characteristics:

melting point: 96° C.-98° C. ¹ H-NMR (200 MHz, CDCl₃) δ (ppm): 1.34 (s, 6H); 2.34 (s, 3H); 4.70 (s, 4H); 7.35 (m, 6H); 7.45 (dd, 2H); 7.90 (dd, 2H); 8.10 (dd, J=1.6 Hz, 1H); 11.58 (s, 1H). ¹³ C-NMR (50 MHz, CDCl₃) δ (ppm): 20.60; 22.90; 236.60; 42.50; 62.30; 117.60; 120.80; 124.80; 127.30; 127.80; 128.30; 128.70; 129.60; 131.70; 136.40; 142.80; 145.10; 155.80; 176.60.

Elemental analysis:

    ______________________________________                                         ELEMENTAL   C.sub.26 H.sub.25 N.sub.5 O.sub.3                                  ANALYSIS    C            H       N                                             ______________________________________                                         CALCULATED  68.6%        5.49%   15.4%                                           FOUND 68.1% 5.43% 15.0%                                                      ______________________________________                                    

EXAMPLE 7 Thermogravimetric Data

Using a standard instrument for thermogravimetric analysis (TA Instrument Model 3000 of Mettler) the following isothermal and gravimetric data are determined relating to Compounds Nr. 1 and Nr. 2 which are compared with the data of Tinuvin 900 produced and sold by Ciba Geigy. The data are indicated in Table 1.

                  TABLE 1                                                          ______________________________________                                                  ISOTHERM AT 280° C.;                                                                    SCANNING AT                                              18 N1/h N.sub.2 ; TIME IN 10° C./min; 18 N1/h                           MINUTES TO INDICATE N.sub.2 ; TEMPERATURE IN                                   LOSS IN WEIGHT OF ° C. TO INDICATE LOSS                                COMPOUND THE STABILIZER IN WT. OF STABILIZER                                 Nr.      10%       50%       10%     50%                                       ______________________________________                                         1        *         --        333     387                                         2 ** -- 309 362                                                                Tinuvin 900 *** 20 281 319                                                   ______________________________________                                          *after 23 minutes;                                                             **after 16 minutes;                                                            ***after 4.2 minutes.                                                    

EXAMPLE 8 Stabilization in Polycarbonate

20 g of bisphenol A polycarbonate are dissolved in 100 ml of methylene chloride, at room temperature under stirring. After several hours, when the polycarbonate has completely dissolved, 0.1 g of Compound Nr. 1 or Compound Nr. 2 or Tinuvin 900 are added (addition equal to 0.5%). For comparative purposes a solution without light stabilizers is prepared.

Films with a thickness of 100 μm are prepared from the above solutions by casting.

The films obtained are subjected to accelerated aging in an Atlas CI 65 Weatherometer under the following conditions:

black panel temperature: 60° C.;

relative humidity: 50%.

Before beginning the aging and afterwards, at regular intervals, the yellow index (YI) of the above films is measured using the method ASTM E 313. The embrittlement time is also analyzed.

The results obtained are indicated in Table 2.

                  TABLE 2                                                          ______________________________________                                         COMPOUND EXPOSURE TIME (h)                                                     Nr.      0      250    500   600  800   1.000 1.500                            ______________________________________                                         --       0.4    4.0    12.4* --   --    --    --                                 1 0.3 3.0 5.0 8.0 9.5 10.6 12.6                                                2 0.5 3.6 5.8 8.7 9.3 10.9 12.7*                                               Tinuvin 900 0.4 3.2 6.0 9.5 10.8   12.0* --                                  ______________________________________                                          *: embrittlement of sample                                                

What is claimed is:
 1. A 2-(2'-hydroxyphenyl)benzotriazole of formula (I): ##STR19## wherein: X represents a hydrogen atom; a halogen atom selected from chlorine or bromine; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₁ -C₁₈ alkoxy group; or a cyano group;R represents a halogen atom selected from chlorine or bromine; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group optionally substituted; a C₇ -C₁₅ aralkyl or C₇ -C₁₅ alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group optionally substituted; a linear or branched C₁ -C₁₈ alkoxy group; a group having the formula: ##STR20## a --COR₄ group or a --NR₅ R₆ group wherein R₄, R₅ and R₆, the same or different, represent a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group optionally substituted; a C₇ -C₁₅ aralkyl or C₇ -C₁₅ alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group optionally substituted; or R represents an ester group of formula (II), (III) or (IV): ##STR21## or an amide group of formula (V): ##STR22## wherein R' represents a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group optionally substituted; a C₇ -C₁₅ arylalkyl or C₇ -C₁₅ alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group optionally substituted; a linear or branched C₁ -C₁₈ alkoxy group; or R represents a 4,4'-ethylidenebisphenol group of formula (VI): ##STR23## R¹ represents a hydrogen atom; a linear or branched C₁ -C₁₈ alkyl group; a linear or branched C₂ -C₁₈ alkenyl group; a linear or branched C₂ -C₁₈ alkinyl group; a C₅ -C₁₈ cycloalkyl group, said cycloalkyl group optionally substituted; a C₇ -C₁₅ aralkyl or C₇ -C₁₅ alkylaryl group; a C₆ -C₁₄ aryl group, said aryl group optionally substituted; an acyl group of formula (VII): ##STR24## or an ester group of formula (VIII): ##STR25## wherein R' has the same meanings described above; R₂ and R₃, the same or different, represent a hydrogen atom; a linear or branched C₁ -C₁₈ alkyl group; or a phenyl group; wherein the substituents of said optionally substituted C₅ -C₁₈ cycloalkyl group and C₆ -C₁₄ aryl groups are halogen atoms selected from chlorine or bromine, linear or branched C₁ -C₁₈ alkyl groups, linear or branched C₂ -C₁₈ alkenyl groups; linear or branched C₂ -C₁₈ alkinyl groups, OH groups, NH groups or SH groups.
 2. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₁ -C₁₈ alkyl groups are: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, t-butyl, t-amyl, 2-ethylhexyl, n-octyl, 1,1,3,3-tetramethylbutyl, n-dodecyl, 1,1,7,7-tetramethyloctyl or n-octadecyl.
 3. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₂ -C₁₈ alkenyl groups are: vinyl, propylene, butylene, pentylene or hexylene.
 4. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₂ -C₁₈ alkinyl groups are: acetylene or propine, butine, 2-butine.
 5. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₅ -C₁₈ cycloalkyl groups, optionally substituted, are: cyclohexyl, cyclopentyl or methylcyclohexyl.
 6. The 2-(2'-hydroxyphenyl)benzotriazoles of formula (I) according to claim 1, wherein the C₇ -C₁₅ arylalkyl groups are: benzyl, 2-phenylethyl or 4-t-butylbenzyl.
 7. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₆ -C₁₄ aryl groups, optionally substituted, are: phenyl, naphthyl, anthracenyl or 2-hydroxyphenyl.
 8. The 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, wherein the C₁ -C₁₈ alkoxy groups are: methoxy, ethoxy, propoxy or n-butoxy.
 9. A 2-(2'-hydroxyphenyl)benzotriazole according to claim 1, having the formula: ##STR26##10.
 10. A 2-(2'-hydroxyphenyl)benzotriazole according to claim 1, having the formula:
 11. A process for the preparation of the 2-(2'-hydroxyphenyl)benzotriazole of formula (I) according to claim 1, comprising reacting a 2-(2'-hydroxyphenyl)benzotriazole of formula (IX): wherein X and R have the same meanings defined in claim 1, with a 2,4-imidazolidinedione-1,3-dimethylol of formula (X) or with a 2,4-imidazolidinedione-1-methylol of formula (Xa): ##STR27## wherein R₂ and R₃ have the same meanings described in claim 1, in the presence of concentrated sulfuric acid, at a concentration ranging from 80% to 96%, at a temperature ranging from -5° C. to +80° C., obtaining a mixture from which the desired compound is isolated by diluting with a water-ice mixture and removing the solid obtained by filtration followed by washing and crystallization in the presence of inert organic solvents.
 12. The process according to claim 11, wherein the inert organic solvents which can be used for the crystallization are: linear or cyclic aliphatic hydrocarbons, aromatic hydrocarbons, alcohols, chlorinated aromatic solvents, ketones, monoalkyl ethers of ethylene glycol. 